Dirt is defined as an output when the fee needed to move it is greater than 1/3 its price in the Bitcoin Core reference implementation. Most of the time, dirt is low-value bitcoins, whose transaction fees are greater than the bitcoins themselves. Because dust is inherently uneconomical to interact with, it is often problematic. By combining separate, low-value outputs, such a transaction becomes a lot more viable. Some pocketbook suppliers give users the option of holding out these functions.

Bitcoin dirt, often called “dust,” means very tiny amounts of Bitcoin that are too small to use in normal transactions. These amounts are usually left over in a wallet after trades or transfers. The problem with Bitcoin dirt is that sending it costs more in fees than the value of the coins themselves, making it impractical to spend. Over time, these tiny pieces can build up and clutter a wallet. Sometimes, hackers use bitcoin dirt in what’s known as a dust attack, where they send small amounts to many addresses to try and track wallet activity. For most users, bitcoin dirt is simply unspendable change that sits in their wallet until fees become cheaper or it is combined.